Operating slide and bolt for firearms



Feb 2, 1954 c. E. SIMPSON 2,667,816

OPERATING SLIDE AND BOLT FOR FIREARMS Original Filed Oct. 29, 1948 2 Sheets-Sheet l Feb. 2, 1954 c. E. slMPsoN OPERATING SLIDE AND BOLT FOR FIREARMS 2 Sheets-Sheet 2 Original Filed Oct. 29, 1948 wwe/wrom,

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Patented Feb. 2, 1,954

T E fil eine OPERATING SLIDE AND BOLT FOR FIREARMS Clarence E. Simpson, Wilbraham, Mass., assigner to the United States of America as represented by the Secretary of War Original application October 29, 1948, Serial No. 57,283. Divided and this application March 16, 1950, Serial No. 150,065

The invention described herein may be manuiactured and used by or for the Government without the payment of any royalty thereon.

This invention relates to gas operated automatic rearms and is particularly directed to a simplified construction wherein a reciprocable operating slide is coupled to a reciprocable bolt only during the interval in which the breech is unlocked and the bolt is free to recoil and counter-recoil.

This application is a division of my copending application Serial No. 57,283, filed October 29, 1948, and now matured into U. S. Patent No. 2,576,973.

In those automatic firearms in which a firing pin is slidably carried within a reciprocating bolt, it is of extreme importance that actuation of the ring pin be delayed until the bolt is securely locked in a battery position. It is also important that unlocking of the bolt be delayed until the relatively high gas pressures generated by the discharge of a cartridge have dropped suiiiciently low to permit safe extraction of the empty cartridge case. Therefore, if an operating slide is used to actuate the bolt, it is necessary that such slide be disassociated from the bolt for certain intervals of time in order that the above-mentioned delays can be eiected. This has been adequately accomplished in the art but has necessitated either the use of rather complicated linkage mechanism for connecting the operating slide to the bolt or has required a camming movement of the bolt away from direct longitudinal reciprocation. Y Y

Consequently, it is an objectof this invention to provide a simple yet reliable latching means for coupling an operating slide to a bolt.

It is a particular object of this invention to provide a bolt and operating slide mechanism wherein the slide will travel independently of the bolt during such time as the latter remains in a locked battery position.

The specic nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a longitudinal cross-sectional view of a firearm embodying the structure of the present invention, the recoiling parts being shown in battery position;

Fig. 2 is a view similar to Fig. 1 but showing the recoiling parts in a fully recoiled position; Fig. 3 is a cross-sectional view of the bolt; Fig. 4 is a top view of the operating slide;

Fig. 5 is a longitudinal sectional view of the operating slide; and

lig. 6 is a rear end view of the firearm receiver.

Referring to the drawings there is illustrated a portion of a firearm embodying the construction of the present invention. The firearm essentially comprises a receiver to the front end of which a barrel 5 is xedly secured as by threads a bolt 8 arranged to reciprocate along suitable longitudinal ways 9 provided within the interior of receiver 5, and an operating slide Ill mounted beneath bolt 8 and also arranged to reciprocate longitudinally along suitable ways H within receiver 5.

Bolt 8 is formed with a substantially cylindrical body portion I2 which terminates in a depending rectangular base'portion I3 arranged to slidably engage in ways 9. A firing pinM is slidably carried in an axial hole I 5 provided through body portion I2 of bolt 8. The rear end of hole I5 is enlarged as shown best at I6 in Fig. 3 and communicates with a substantially rectangular opening Il extending upwardly from the bottom of bolt 8 and having a front and rear wall surface indicated by 25 and 2li, respectively. The junction of the enlarged rear end portion I5 of'lring pin hole I5 and rectangular opening II provides access for a tang portion I8 integrally formed at the rear end of iiring pin I4'. A substantially semi-annular groove I9 is providedat the f0r Ward end of cylindrical body portion I2 of bolt t and is arranged to seat a mating bolt lock 2t which is slidably mounted for vertical movement in a suitable guideway 2| formed in receiver 5.

Operating slide I is a substantially rectangular member having a longitudinally extending slot 22 through which bolt lock 20 is arranged to extend. A vertically disposed lug 23 projects upwardly from the rear end of slide I and is arranged to extend into rectangular opening I'I of bolt 8 and contact wall surfaces 24 and 25 in a manner to be hereinafter'explained. A transverse slot 26 in operating slide lug 23 is arranged to receive tang I8 of iiring pin I4, Thus operating slide II) serves as a hammer and actuates ring pin I4 to discharge a cartridge 21. Suitable cam grooves 28 and 29 are formed in the top and bottom surfaces of operating slide I0 and are arranged to actuate bolt lock 20 in a manner fully described in the aforementioned U. S. Patent No. 2,576,973.

In the battery position of bolt 8 and slide I0, a iront end portion 30 of the latter projects forwardly beyond the end of receiver 5 into a rectangular housing 3| suitably secured beneath barrel 6 and parallel thereto. Front end portion 30 of slide IU is provided witha. threaded longitudinal hole 32- arranged-to receive `the rear.- end of a hollow operating piston 33.` An operating spring 34 and guide rod 35 are associated with piston 33 in a manner fully disclosed in Patent No.2,476,328, dated July 19, 1949. n K A The rear end of longitudinal slot 22 in opere-.-v ating slide l is extended to form a narrower slot portion 36 arranged to recei-*ve{a}latchlf3*'l1 which" is pivotally secured to slide "f as by'a transverse pin 38. Latch 31 is a substantially L-shaped member having a short andiailongilegportione- Simultaneously with the completion of such chambering, the iront end of latch leg `49 contactsrcam surface 49 on boltlock 20 and is thereby disengaged from bolt'shoulder 46. As a result,

.slide I0 moves forwardly to actuate bolt lock 20 Vinto .engagement With semi-annular groove I9.

Opera-tingpslide .t9 then continues to move forwardly and actuate firing pin I4 to re cartridge 2l whereupon the firing cycle is repeated.

39 and 40, respectively, and.issarramged-.ztofbe disposed Within s1ot portion 36 so that short leg portion 39 contacts the rear wall of slotfportion. 36, such wall being rearwardly inclined as lshown at 4| in Fig. 5. An angularly disposent-cylindrical... recess 42 extends into slide l0 beneath lug 2321- and is arranged to seat a `"spring 43 and a slidable plunger 44 which. contactslegfportion 39 of latch 31' 'and provides `bias thereto infafeountereloek. wise direction.- A..latching.shoulrler. t5 lis ,-1120- vided on leg portion 40 and is arranged to mate with an `oppositely formedshoulder Az--onfgthe bottom of bolt 8. Theorward-end lof l eg;por.l tion 49. of latch 3T isbeveled jaa shoivrifat; 41ste. permit positive entryv thereofinto-ajiectanguflaropening 48, extending through -boltdoek 23. -Th'eupper wall of-bolt.. lockv .opening-18: is provided..

with a cam surface. `49 arranged. to bef-contacted. by the front end of -leg;f-port ion.40. @tinten-31e In. the battery position illustrated-mFigyl.: operating slide l0. ism-fully.r forwardginpcontact with the front wall 25 formed inif-bolt8 yqreci-f tangular opening 1.1. LegA portion-4350i :latch 31. proj ectsY forwardly through rectang-,iilar1..open-v ing l43 in bolt, lticlrfil).4 When: cartridge:.-.2"|- .-isv discharged .by firing pin vI4,.-th(ef-generatedgasesl actv upon the frontend' (not shown)- ofoperating,- piston 33 andfproyide recoil-movementthereto..

Since bolt-lock is engaged-with groove l 9 in bolt 8, ,only thebperating slide:--|-moves:reary wardlyv and retractsy Yiringpin` (4.1 -As -slid'erj recoils.. bolt lool; 20.. Ais cammedfnpwardly to dise. engage from bolt: 8- vvhereuponithe i latteris-f-riee: to. recoil. as soon-.asqvertical lug-23-onslide d0.

contactsthe rear.- -wal1 2 4- inf-bolt- 8. --urin'g-fthis..

sgi-called` ffdWell-fperiod latch-` 31.- has been; withi-..

drawn from, rectangular openingf48 fin-boltv lock.; 50

2,0 .and has-been; rotated by spring.-biasediplun'gerrv 44 --so-v that latch-shoulder 45--isjengaged-ffwithz shoulder 45,. onfbolt 8.1 Operating'slide.-l(ir-and'.

boltf 8 recoil; simultaneously.- and *Contact sa suit-2 able.- buffer: plate;.50.;-.provided a-tfthe rean endeoff receiver; 5. Since operating spring Minas been compressed during-recoil, suicient energy-has been stored toy provide for counter-recoil move'- ment. y

Bolt 8v and operating slidel l0 continue tomove together" during `counter-recoil. due to. the.. engagement ofY 1atchj3'l. Cartridge 21 has been positioned by suitable. feeding mechanism..` (not shown)V in..frontof..bolt8.so that such'cartrdge.

can be. chambered 'as bolt V8v continuesl fo'rv'ia'rdlyL\.`

Y Itwill thusbe readily apparent to those skilled inthe .art that there is here provided a simple yet positive connection between an operating s1ide.;.and .bolt....which will permit movement of thettwo: members as a unit and yet assure dis- -engagementtherebetween at exactly the proper times, to permit a dwell period during unlocking oi" vthebolt upon recoil and a safe period during counter-recol-so ythat the bolt can be positively locked prior to actuation of the firing pin.

I claim: Y In Ya :rearm having a receiver, a. boltr `slida-bly mountedv in-Ythe receiver ynar-reciprocating. move-- ment betweenabattery position-.anda `recoiled position, a reciprocable operating slidesiidabl'y mounted.v in saidl receiver ybeneath said bolt, .verticalz. lugy means adjacent the.. rear yend. of. said operating. slide, a firing pin slidably carried in said-.bolt and having a dependingtangportion at therea-r end-thereof, said-bolt having an opening extending upwardly from the bottom: thereof arranged .to receive. saidv` luglrrleansgin.Y engagement-.Withsaidring. pin tang portion, said open.-

ing-...insa-idboltv being of greater lengththan. said lug means whereby said operating-slid'e-is 1 freeto reciprocate relative tov said bolt, a shoulder in .'the.- `bottom v-O-.said bolt disposed forwardly of said opening, therein, latch means pivotally. se-

cured-.toasaid opera-ting slide, resilient means for biasing .saidrlatchl Ainto engagement with said shoulder. at the conclusion oi the rear-.wardmovement of saidslide relative to-said bolt whereby saidbolt .and said-slide reciprocate. together, and means. for. disengaging said; latch from said bolt whenthe latter has. reached battery position 4 whereupon saidv slide.- is free to. move forwardly andfactuate said ring pin.. g y

CLARENCE E. SIMPSON.

References Cited in the le` 0I" this.. patent 

